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Abstract

Fast patrol boats are high-speed vessels operated by the Royal Norwegian Navy (RNoN). These ships are 36,5 meters long, have a beam of 6,2 meters and operate at high speed (32 knots – 16,5 meters per second) in very restricted waters. The fast patrol boats are war ships and navigation tasks performed by the crews are different from those in civilian high-speed craft. A team of five persons navigate the fast patrol boats, and navigation is based on traditional means such as visual observations and paper charts. The person leading the team is the navigator.

The ships were built in the late 1970s and upgraded in 2001 when new navigation equipment was installed. However, the crews criticized the modern navigation equipment for being complex and difficult to use. In 2002, an upgraded fast patrol boat collided with a rock during high-speed navigation. The accident resulted only in material damage. Following this accident the RNoN acknowledged the need to gather knowledge about human factors and design of navigation equipment.

Navigating a fast patrol boat is about operating a complex sociotechnical system. Strong demands are put on both people and their tools. In order to design usable navigation equipment for these ships, one has to have knowledge about the ships’ task, the crew that carry out the navigation, and the contexts in which navigation takes place. To gather such knowledge, this study observed several navigation teams at work and used different approaches to structure and describe the work of navigation teams.

A hierarchical task analysis was conducted in order to describe navigation in accordance with procedures and established best practices. The assignment navigate to destination was the highest level of the navigator’s work. The assignment included the navigation tasks; plan, start, monitor, change course, and arrive. For each navigation task, a detailed analysis was conducted. It was found that the crews used work practices that emphasize efficiency rather than accuracy in e.g. position fixing. Although efficiency was given priority, the navigation teams controlled system variation in order to keep the ship within safe waters.

A usability study was conducted. This study treated navigation equipment that had been fitted when the ship was upgraded. A cognitive walkthrough was conducted in order to evaluate whether human factors guidelines were applied in the design of the modern navigation equipment. In total 30 usability findings were described. The study suggested that navigation equipment to little extent were user-centered. The navigation teams compensated for lack of usability by expanding actions and by modifying the equipment.

The framework of distributed cognition was used to describe the observed work of the navigation teams. Distributed cognition suggests that cognitive processes are not bounded by the individual person, but are distributed between humans and the physical artifacts they use. Humans and artifacts that participate in goal directed processes are said to be in a functional relationship. Within the functional relationships information trajectories describe how information is gathered, shared and used. Functional relationships are not static but can configure depending on the context. In studies of distributed cognitive processes, investigating physical representations are important as these are outside the head of the people, yet within the cognitive system.

The navigation team and their artifacts were described as one cognitive system where the crew and their tools were functionally related. Navigation was in most cases founded on a detailed plan. The navigator drew lines and symbols in nautical paper charts in order to represent the plan. The navigation plan was a resource for the teams’ actions and the charts were a frame of reference for the teamwork on the bridge. The crew enriched their tools in order to improve communication and information retrieving. For instance, information important to navigation was to large extent noted in the chart. Another example was equipping the bearing device with small pins in order to feel the direction of the device. Artifacts were also used to support the navigators’ memory. Pointing the bearing device in the direction of the upcoming course meant that the navigator did not have to remember the sailing direction. The dynamic properties of the system did on the one hand provide barriers towards erroneous actions. The crewmembers monitored each other’s tasks and corrected mistakes when necessary. On the other hand, when the functional relationship was not held together, the result was entropy.

The framework of activity theory was used to provide further descriptions of the navigation teams’ work. Activity theory focuses on people working in a context. In this study, activity was regarded as situated actions taking place in shorter time frames. Activity theory claims that the elements of the activity encompass the persons and their use of tools towards a conscious goal. Further, the goals of the activity are influenced by the outcome of the activity and by specific constraints.

Activity theory describes the structure of navigation at different levels. The basic constraints that influenced the navigation teams were related to the space available to maneuver the ship, and to the conditions for making visual observations. Crewmembers’ behavior was not constant, but directed towards different motives depending on the circumstances. The crew usually carried out goal related tasks. However, in some cases the crew directed their work towards the operations of equipment or towards solving problems. The framework of activity theory described how internal and external factors influenced the focus of the teams’ work.

Both distributed cognition and activity theory findings suggested that the teams frequently used artifacts for purposes beyond their initial scope of design. For instance, bearing devices were used to augment navigators’ memory.

Based on the knowledge gathered from task analysis, the usability study, and from the frameworks of distributed cognition and activity theory, a design study was carried out. Four prototypes were produced in order to explore possible design solutions that could improve the thinking and cooperation for the navigation teams. The prototypes included an automatic steering system, an electronic chart, alarm panels, and audio alarms. The prototypes emphasized the use of physical representations and perceptually rich interfaces. The interfaces used for instance sound, vision, and tacitle feedback.

Applying human factors principles in design suggested several design solutions that possibly could improve navigators’ working conditions. However, there is a risk that new design will create opportunities for new types of failures. For this reasons, user evaluations were suggested as a necessary part of design development. However, user evaluation was outside the scope of this study.

This study suggested two outcomes of a design processes. One outcome is the improvement of the design in question. The second outcome is the design seeds, that is concepts and techniques that can be reused in other development settings.

Development on navigation technology is at present an industry with strong engineering influence and traditions. This study suggested that a user-centered approach should involve engineers and work through the engineers’ domain. It was suggested that a design process for development of navigation equipment would benefit from being multidisciplinary, iterative and utilize user evaluation.